Widodo, Agus, et al. “PENGARUH PEMBERIAN TUMMY TIME EXERCISE TERHADAP PENINGKATAN KEMAMPUAN GROSS MOTORIC HEAD CONTROL AND ROLLING PADA ANAK USIA 0-16 MINGGU”. Prosiding University Research Colloquium, Jan. 2019, pp. 11-15, https://repository.urecol.org/index.php/proceeding/article/view/291.